In a data communication system, it is important to deliver data from a transmitter to a receiver without any error. In 1948, Shannon mathematically defined a limit of a maximum data transmission rate that can be delivered without error. This is referred to a channel capacity. In order to implement an actual communication system having a data transmission rate most approximate to such channel capacity, an error correction code having a complexity that can be implemented is required. Since 1948, various types of error correction codes have been developed. Among the recently developed error correction codes, the turbo code and Low Density Parity Check (LDPC) have been known to perform with a channel capacity that is relatively most approximate to Shannon's channel capacity. However, although such codes demonstrate performance that is most approximate to Shannon's channel capacity, they do not achieve the accurate channel capacity. Recently, in the process of resolving the above-described problems, the polar code, which fully satisfies and achieves the channel capacity mathematically, has been developed.
The Hybrid Automatic Repeat request (HARQ) corresponds to an error recovery technique, which is performed by requesting re-transmission of a packet, when a packet having an error is received. Diverse development has also been carried out on HARQ methods based on polar codes (or polar coding). However, according to the methods that have been proposed up to this day, such methods have not been developed as a means of enhancing channel polarization of information, which corresponds to a basic concept of polar coding.